scholarly journals Entropy of systems

2016 ◽  
Vol 38 (3) ◽  
pp. 1118-1126
Author(s):  
RADU B. MUNTEANU
Keyword(s):  
Positive Integer ◽  
Probability Space ◽  
Bernoulli Shift ◽  
Ergodic Measure ◽  
Measure Preserving Transformation ◽  
Zero Entropy ◽  
Standard Probability

In this paper we show that any ergodic measure preserving transformation of a standard probability space which is $\text{AT}(n)$ for some positive integer $n$ has zero entropy. We show that for every positive integer $n$ any Bernoulli shift is not $\text{AT}(n)$. We also give an example of a transformation which has zero entropy but does not have property $\text{AT}(n)$ for any integer $n\geq 1$.

scholarly journals Groups with infinite FC-center have the Schmidt property

2021 ◽  
pp. 1-46
Author(s):  
YOSHIKATA KIDA ◽  
ROBIN TUCKER-DROB
Keyword(s):  
Probability Space ◽  
Amenable Group ◽  
Ergodic Measure ◽  
Countable Group ◽  
Full Group ◽  
Orbit Equivalence ◽  
Central Sequence ◽  
Property T ◽  
Finite Conjugacy ◽  
Standard Probability

Abstract We show that every countable group with infinite finite conjugacy (FC)-center has the Schmidt property, that is, admits a free, ergodic, measure-preserving action on a standard probability space such that the full group of the associated orbit equivalence relation contains a non-trivial central sequence. As a consequence, every countable, inner amenable group with property (T) has the Schmidt property.

scholarly journals (Uniform) convergence of twisted ergodic averages

2015 ◽  
Vol 36 (7) ◽  
pp. 2172-2202 ◽  
Author(s):  
TANJA EISNER ◽  
BEN KRAUSE
Keyword(s):  
Uniform Convergence ◽  
Probability Space ◽  
Elementary Proof ◽  
Ergodic Measure ◽  
Ergodic Averages ◽  
Almost Everywhere ◽  
Measure Preserving Transformation ◽  
Image Position ◽  
Badly Approximable

Let$T$be an ergodic measure-preserving transformation on a non-atomic probability space$(X,\unicode[STIX]{x1D6F4},\unicode[STIX]{x1D707})$. We prove uniform extensions of the Wiener–Wintner theorem in two settings: for averages involving weights coming from Hardy field functions $p$,$$\begin{eqnarray}\displaystyle \bigg\{\frac{1}{N}\mathop{\sum }_{n\leq N}e(p(n))T^{n}f(x)\bigg\}; & & \displaystyle \nonumber\end{eqnarray}$$and for ‘twisted’ polynomial ergodic averages,$$\begin{eqnarray}\displaystyle \bigg\{\frac{1}{N}\mathop{\sum }_{n\leq N}e(n\unicode[STIX]{x1D703})T^{P(n)}f(x)\bigg\} & & \displaystyle \nonumber\end{eqnarray}$$for certain classes of badly approximable$\unicode[STIX]{x1D703}\in [0,1]$. We also give an elementary proof that the above twisted polynomial averages converge pointwise$\unicode[STIX]{x1D707}$-almost everywhere for$f\in L^{p}(X),p>1,$and arbitrary$\unicode[STIX]{x1D703}\in [0,1]$.

On Ergodic Extensions of Stationary Measures with Minimal Support

1983 ◽  
Vol 26 (1) ◽  
pp. 20-25
Author(s):  
William B. Krebs ◽  
James B. Robertson
Keyword(s):  
Positive Integer ◽  
Discrete Spectrum ◽  
Ergodic Measure ◽  
Finite Partition ◽  
Minimal Support ◽  
Stationary Measures ◽  
Root Of Unity ◽  
Measure Preserving Transformation

AbstractLet T be an ergodic measure preserving transformation with the following property: there exists a positive integer n and a finite partition α such that the number of atom of is one more than that of , and the probability of at least one of the atoms is irrational. Then there exists a unique (up to conjugacy) transformation S such that there is a partition β with S restricted to isomorphic to T restricted to and the number of atoms in is one more than the number of atoms in for all m ≥ n. Moreover this transformation has discrete spectrum with at most two generators. If there are two generators, one of them must be a root of unity.

scholarly journals Two special subgroups of the universal sofic group

2018 ◽  
Vol 39 (12) ◽  
pp. 3250-3261
Author(s):  
MATTEO CAVALERI ◽  
RADU B. MUNTEANU ◽  
LIVIU PĂUNESCU
Keyword(s):  
Probability Space ◽  
Group Of Automorphisms ◽  
Abelian Subalgebra ◽  
Standard Probability

We define a subgroup of the universal sofic group, obtained as the normalizer of a separable abelian subalgebra. This subgroup can be obtained as an extension by the group of automorphisms on a standard probability space. We show that each sofic representation can be conjugated inside this subgroup.

The behavior of Bernoulli shifts relative to their factors

1999 ◽  
Vol 19 (5) ◽  
pp. 1255-1280 ◽  
Author(s):  
CHRISTOPHER HOFFMAN
Keyword(s):  
Bernoulli Shift ◽  
Bernoulli Shifts ◽  
Ergodic Transformations ◽  
Zero Entropy ◽  
Almost All

We present numerous examples of ways that a Bernoulli shift can behave relative to a family of factors. This shows the similarities between the properties which collections of ergodic transformations can have and the behavior of a Bernoulli shift relative to a collection of its factors. For example, we construct a family of factors of a Bernoulli shift which have the same entropy, and any extension of one of these factors has more entropy, yet no two of these factors sit the same. This is the relative analog of Ornstein and Shields uncountable collection of nonisomorphic $K$ transformations of the same entropy. We are able to construct relative analogs of almost all the zero entropy counter-examples constructed by Rudolph (1979), as well as the $K$ counterexamples constructed by Hoffman (1997). This paper provides a solution to a problem posed by Ornstein (1975).

scholarly journals Measure-theoretic chaos

2012 ◽  
Vol 34 (1) ◽  
pp. 110-131 ◽  
Author(s):  
TOMASZ DOWNAROWICZ ◽  
YVES LACROIX
Keyword(s):  
Ergodic Measure ◽  
Uniform Measure ◽  
Ergodic System ◽  
Topological System ◽  
Ergodic Measures ◽  
Topological Chaos ◽  
Probability Spaces ◽  
Entropy Zero ◽  
Standard Probability

AbstractWe define new isomorphism invariants for ergodic measure-preserving systems on standard probability spaces, called measure-theoretic chaos and measure-theoretic$^+$ chaos. These notions are analogs of the topological chaos DC2 and its slightly stronger version (which we denote by $\text {DC}1\frac 12$). We prove that: (1) if a topological system is measure-theoretically (measure-theoretically$^+$) chaotic with respect to at least one of its ergodic measures then it is topologically DC2 $(\text {DC}1\frac 12)$ chaotic; (2) every ergodic system with positive Kolmogorov–Sinai entropy is measure-theoretically$^+$ chaotic (even in a slightly stronger uniform sense). We provide an example showing that the latter statement cannot be reversed, that is, of a system of entropy zero with uniform measure-theoretic$^+$chaos.

The Pointwise Ergodic Theorem for Transformations whose Orbits contain or are contained in the Orbits of a Measure-Preserving Transformation

1982 ◽  
Vol 34 (6) ◽  
pp. 1303-1318 ◽  
Author(s):  
John C. Kieffer ◽  
Maurice Rahe
Keyword(s):  
Information Theory ◽  
Ergodic Theory ◽  
Probability Space ◽  
Sufficient Conditions ◽  
Measurable Transformation ◽  
Input And Output ◽  
Measure Preserving Transformation ◽  
Image Position ◽  
Necessary And Sufficient ◽  
Measure Preserving Transformations

1. Introduction. Let be a probability space with standard. Let T be a bimeasurable one-to-one map of Ω onto itself. Let U: Ω → Ω be another measurable transformation whose orbits are contained in the T-orbits; that is,where Z denotes the set of integers. (This is equivalent to saying that there is a measurable mapping L: Ω → Z such that U(ω) = TL(ω)(ω), ω ∈ Ω.) Such pairs (T, U) arise quite naturally in ergodic theory and information theory. (For example, in ergodic theory, one can see such pairs in the study of the full group of a transformation [1]; in information theory, such a pair can be associated with the input and output of a variable-length source encoder [2] [3].) Neveu [4] obtained necessary and sufficient conditions for U to be measure-preserving if T is measure-preserving. However, if U fails to be measure-preserving, U might still possess many of the features of measure-preserving transformations.

Strong Poincaré recurrence theorem in MV-algebras

2010 ◽  
Vol 60 (5) ◽  
Author(s):  
Beloslav Riečan
Keyword(s):  
Probability Space ◽  
Mv Algebra ◽  
Measure Preserving Transformation ◽  
Poincaré Recurrence Theorem ◽  
Recurrence Theorem ◽  
Poincare Recurrence ◽  
Poincaré Recurrence ◽  
Almost All ◽  
Poincare Theorem ◽  
Mv Algebras

AbstractThe classical Poincaré strong recurrence theorem states that for any probability space (Ω, ℒ, P), any P-measure preserving transformation T, and any A ∈ ℒ, almost all points of A return to A infinitely many times. In the present paper the Poincaré theorem is proved when the σ-algebra ℒ is substituted by an MV-algebra of a special type. Another approach is used in [RIEČAN, B.: Poincaré recurrence theorem in MV-algebras. In: Proc. IFSA-EUSFLAT 2009 (To appear)], where the weak variant of the theorem is proved, of course, for arbitrary MV-algebras. Such generalizations were already done in the literature, e.g. for quantum logic, see [DVUREČENSKIJ, A.: On some properties of transformations of a logic, Math. Slovaca 26 (1976), 131–137.

Mixing on Sequences

1983 ◽  
Vol 35 (2) ◽  
pp. 339-352 ◽  
Author(s):  
Nathaniel A. Friedman
Keyword(s):  
Ergodic Measure ◽  
General Definition ◽  
Weak Mixing ◽  
Independent Sequence ◽  
Density Zero ◽  
Measure Preserving Transformation ◽  
Upper Density ◽  
Mixing Sequences ◽  
Definition Of ◽  
Single Sequence

Our aim is to study the mixing sequences of a weak mixing transformation. An ergodic measure preserving transformation is weak mixing if and only if for each pair of sets there exists a sequence of density one on which the transformation mixes the sets [9]. An unpublished result of S. Kakutani implies there actually exists a single sequence of density one on which the transformation is mixing for all sets (see Section 3). This result motivated the general définition of a transformation being mixing on a sequence, as well as mixing of higher order on a sequence. Given a weak mixing transformation, there exist sequences along which it is mixing of all degrees. In particular, this is the case for an eventually independent sequence [7].In Section 3 it will be shown that if T is weak mixing but not mixing, then a sequence on which T is two-mixing must have upper density zero.

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